Method and Apparatus for Vitamin D Enhancement in Mushrooms

ABSTRACT

An apparatus and method for increasing Vitamin D content in mushrooms is disclosed. A mushroom slurry of comminuted or pulverized mushrooms or mushroom parts and liquid, such as water, is passed under a UV light source. The slurry may be conveyed to the UV light source by a vibrating conveyor. After UV light exposure, the treated slurry may be dried and ground into a powder, or the treated slurry may be filtered and the insoluble portion may be dried and ground into a powder. The irradiated mushroom powder has a mass fraction of Vitamin D2 of at least 2500 IU/gram of powder, and more preferably at least 20,000 IU/gram of powder. Irradiated mushroom powder may be incorporated into consumable food product for humans or animals, and/or may be incorporated into topical preparations for cosmetic use.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/115,922, filed Aug. 29, 2018, now pending, which was a divisionalapplication under 35 U.S.C. § 121 claiming priority to U.S. patentapplication Ser. No. 15/075,764, filed Mar. 21, 2016, now abandoned,which was a continuation-in-part of U.S. patent application Ser. No.13/628,194, filed Sep. 27, 2012, now U.S. Pat. No. 9,326,540, thecontents of each of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to a method and apparatus for increasing VitaminD content in a mushroom slurry comprising a fluid, such as water, andfresh mushrooms, or mushroom parts, spawn and/or mycelia. The slurry isexposed to a broad spectrum of light for a specified period of time,using an electric glow discharge lamp. The slurry then is filtered toremove excess water and undesirable soluble materials. The remainingfilter cake is dried and ground into a powder. The resulting mushroompowder has high levels of Vitamin D2, and is all natural, vegetarian,and can be used as an ingredient to fortify foods or as a dietarysupplement.

2. Description of the Prior Art

The two major forms of Vitamin D are Vitamin D2 and D3. Vitamin D2 isnot produced by the human body and is only derived from fungi and plantsources. Vitamin D3 is produced in human skin through exposure tosunlight. The benefits of Vitamin D are numerous, and deficiency of thevitamin in humans can lead to several diseases. Because human exposureto sunlight for prolonged periods is impractical, in order to receivethe benefits and overcome potential deficiencies of Vitamin D, there isa need for a method and an apparatus to increase Vitamin D2 in mushroomsand in dried mushroom powder to create a foodsource for this importantvitamin.

Commercially grown mushrooms contain very low levels of Vitamin D2,typically less than 20 International Units (IU) per 85 gram standardfresh serving. 40 IU of Vitamin D2 equals 1 microgram. Mushrooms,however, naturally contain ergosterol, a biological precursor to VitaminD2. Research shows that ergosterol in several species of mushroomsconverts to Vitamin D2 when exposed to UV light. White button mushrooms,brown portobello mushrooms, shiitake mushrooms, and oyster mushrooms aresome types of mushrooms known to show a Vitamin D2 response when exposedto UV light. With sufficient duration and exposure, the level of VitaminD2 in these and other mushroom species can reach or exceed 400 IU/85 gof fresh mushrooms, equating to 100% of the current recommended DailyValue for Vitamin D in the United States.

To increase Vitamin D level in mushrooms, certain methods in thebackground art require mushroom exposure to UV light for extendedperiods to achieve a significant increase in the level of Vitamin D. Inone method, exposure times from 1 hour to 24 hours were required. Inother methods, 20 minutes to 60 minutes of exposure time were required.See Jasinghe, V. J., Perera, C. O., “Distribution of ergosterol indifferent tissues of mushrooms and its effect on the conversion ofergosterol to vitamin D2 by UV irradiation,” Food Chem. (2005), 92, pp.541-46; Jasinghe, V. J., Perera, C. O., “UV irradiation: The generatorof Vitamin D2 in edible mushrooms,” Food Chem. (2006), 95, pp. 638-43;and Jasinghe, V. J. “Conversion of ergosterol in edible mushrooms toVitamin D2 by UV radiation,” Thesis submitted to the Department ofChemistry, National University of Singapore (2005).

The prior work to increase Vitamin D content in mushrooms relates totreating fresh mushrooms with UV light. Photolytic treatment of driedmushroom powder to produce high levels of Vitamin D2 has also beentaught. Alternative methods for treating commercially viable quantitiesof mushrooms for short treatment times to produce foods or foodadditives with high Vitamin D2 content continue to be sought.

SUMMARY OF INVENTION

One embodiment of the present invention is a method for increasingVitamin D content of mushrooms by treating a mushroom slurry formed ofmushroom particles suspended in a liquid. Preferably, the mushroomslurry comprises mushroom particles suspended in a liquid, such aswater, in a ratio of at least 3:1 (by weight) water to mushroomparticles.

The mushroom slurry having mushroom particles of particle sizes of about200 microns or less is irradiated with one or more pulses of ultravioletlight with wavelengths in the range of about 200 to about 800 nanometersemitted by an electric glow discharge lamp, such as a xenon lamp.Alternative sources of ultraviolet light may be used, including mediumpressure mercury vapor lamps, low pressure mercury vapor lamps,microwave powered fusion ultraviolet lamps, light emitting diodes(LEDs), and low pressure amalgam lamps. Preferably, the mushroomparticle sizes in the mushroom slurry are about 100 microns or lessbefore the slurry is irradiated. Ideally, the mushroom slurry isvibrated as it is irradiated.

After irradiating, the mushroom slurry may be dried and the remainingsolids ground to form a powder. More preferably, after irradiating, themushroom slurry is filtered to remove excess liquid. The remainingfilter cake is dried and ground into a powder. The resulting irradiatedmushroom powder has a Vitamin D2 level of at least 2500 IU/gram,preferably at least 7500 IU/gram, and most preferably at least 20000IU/gram. This irradiated mushroom powder may be used as a condiment tobe sprinkled on or into foods, or may be incorporated into a consumablefood product, including food for human consumption as well as animalfeed. The irradiated mushroom powder alternatively may be incorporatedinto topical preparations for cosmetic use.

The mushroom powder may be made from one or more mushrooms of varioustypes, including but not limited to, white button mushrooms, brownportobello mushrooms, shiitake mushrooms, maitake mushrooms, oystermushrooms, agaricus bisporus, and mixtures thereof.

The mushroom slurry is prepared by combining fresh mushrooms or mushroompieces or particles with a liquid, such as water, and then passing themixture through a high shear mixer or a pressure reactor, such as ahomogenizer, or both a high shear mixer and a pressure reactor. Thepressure reactor is preferred as it is able to rupture or destroyindividual cell walls of the mushroom tissue thus releasing the contentsof the cells into the slurry liquid. The pressure reactor uses acombination of pressure drop to explode the cell walls as the mushroomslurry is passed through a chamber, followed by contacting the slurrywith a window or wall within the chamber to further ensure celldestruction. This greater comminution or pulverizing of the mushroomtissues in the slurry allows for greater efficiency of convertingergosterol to Vitamin D2 using a pulsed light.

If pulsed ultraviolet light is used, the source of pulsed lightpreferably is an electric glow discharge lamp capable of emitting pulsesof light with wavelengths in the range of about 200 to about 800nanometers, such as a xenon lamp. Preferably, the electric glowdischarge lamp is enclosed in a light chamber that is provided withmeans for controlling temperature therein, such as a blower and exhaust.A conveyor may convey the mushroom slurry for exposure to one or morepulses of light by the lamp. Preferably, the conveyor is a type thatshakes or vibrates the mushroom slurry as it is conveyed for exposure toradiation. Examples are vibrating conveyors, shaker tables, vibratingpans and vibrating chutes. The UV light-treated slurry may be collectedand recirculated one or more times for further exposure to UV lightpulses.

A batch type system also can be used in which a vessel is equipped witha UV or pulsed light that is submerged in the mushroom slurry or isfixed to the sides of the vessel. The slurry is then mixed or agitatedfor a fixed period of time to convert the ergosterol to Vitamin D.

After the slurry has been exposed to the UV light source for one or morepasses, it may be dried to remove the liquid. The dried solids may thenbe ground into powder. More preferably, after the slurry has beenexposed to the UV light source, the slurry is filtered to separate theinsoluble fraction from the soluble fraction. The soluble materials donot contain high levels of Vitamin D and may be discarded. Vitamin D iswater insoluble and by removing the water soluble portions of the slurrythe remaining insoluble portion now contains extremely high levels ofVitamin D. The insoluble portion, or filter cake is then dried andground into a powder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front elevational view of an apparatus fortreating a mushroom slurry with UV radiation;

FIG. 2 is a schematic front elevational view of an alternative apparatusfor treating a mushroom slurry with UV radiation;

FIG. 3 is a representative plot of relative irradiance versus wavelengthof light that is generated by a xenon pulsed UV light emitting electricglow discharge lamp; and

FIG. 4 is a flowchart diagram of one method for increasing the Vitamin Dcontent of mushrooms.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As a first step, fresh mushrooms are cultivated using traditionalmethods. After harvesting, any part of the mushroom can be usedincluding stems, caps, stumps, waste material from the slicing process,or culls otherwise unfit for sale to the fresh market.

The growing medium used to produce the mushrooms can also be considereda raw material source for production of animal feed type products. Theseed or source material used to grow mushrooms commonly referred to asspawn can also be used.

Referring now to FIG. 4, the whole mushrooms or mushroom pieces areshredded into pieces as an optional first step 102. Next, the mushroompieces are combined with a suitable liquid or fluid, such as water orwater mixed with ethanol or water mixed with propylene glycol, using ahigh shear mixer to produce a slurry (step 104 in FIG. 3). Suitable highshear mixers include models BX60 and DX60 from Silverson Mixer ofMassachusetts. The mushroom slurry also may be formed using a Waringblender or a colloid type mill.

Preferably, the slurry is then passed through a pressure reactor orhomogenizer capable of producing a pressure drop to explode individualcells contained within the mushroom tissue (step 106 in FIG. 4). Whilenot wishing to be bound by any one theory, it is believed that the cellsof the mushroom tissue release their contents, including ergosterol,into the slurry fluid or liquid in such pressure reactor or homogenizer.The high shear mixer may be sufficient to homogenize or emulsify themushrooms into a flowable slurry. In such a case, the slurry may by-passthe pressure reactor (step 105) in FIG. 4.

Alternatively, or additionally, one or more enzymes may be added to theslurry to break apart or destroy the mushroom cells to disperse cellcomponents into the slurry. Representative enzymes for this purposeinclude cellulase and chitinase.

The mushroom slurry preferably has a composition of liquid and mushroomparticles in a ratio of at least 3:1 (by weight) liquid to mushroomparticles, more preferably at least 4:1 (by weight) liquid to mushroomparticles.

Next, the resulting slurry is passed under a source of UV light, such aspulsed UV light. Various sources of UV light may be used, including butnot limited to, electric glow discharge lamps, medium pressure mercuryvapor lamps, low pressure mercury vapor lamps, microwave powered fusionultraviolet lamps, light emitting diodes (LEDs), and low pressureamalgam lamps. Preferably, the slurry is conveyed by means of avibrating conveyor (step 108 in FIG. 4). Alternatives to the vibratingconveyor include a shaker table, a vibrating pan and a vibrating chute.

If a pulsed UV light source is used, the pulsed UV light emits up tothree (3) pulses of light per second, and is powerful enough to converta very high percentage of ergosterol present in the slurry to vitamin D.Longer exposure times to the pulsed light appear to produce higherergosterol conversion to vitamin D. Optionally, the slurry may berecirculated and passed under the source of UV light, such as a pulsedUV light source, more than one time for more than one exposure (step 110in FIG. 4).

We have found that particle size can impact the level of Vitamin D thatcan be achieved in the mushroom slurry. What we discovered is thatwhatever the UV light source used, the UV exposure only convertsergosterol to vitamin D to a narrow optical depth. Slurries that containmushroom solids or powders with an average particle size of about 50-75microns provide optimal results for efficient conversion of ergosterolto Vitamin D2.

Vitamin D is considered a fat soluble vitamin. It is therefore containedin the insoluble portion of the mushroom slurry. After exposure to UVlight, the slurry is filtered to separate the soluble and insolublefractions (step 112 in FIG. 3). The soluble fraction contains primarilydissolved polysaccharides, such as sugars. The insoluble fractioncontains primarily chitin, which comprises the cell walls of themushroom tissue, some proteins, and very high levels of vitamin D. Theinsoluble fraction, or filter cake, is retained, and the solublefraction is discarded. Suitable filtering means include standardlaboratory grade filter paper, a filter bag with a desired micron size,a filter press and/or a centrifuge.

The filter cake is then dried to produce a shelf stable low moistureproduct having a moisture content of less than about 30% moisture byweight (step 114 in FIG. 3). This shelf stable low moisture product(mushroom powder) typically has about 8-15% moisture by weight. Thefilter cake may be dried in a number of ways, including but not limitedto a batch type process using air convection, or a fluid bed type dryer,as well as a combination type apparatus that performs drying andgrinding simultaneously.

The dried mushroom slurry filter cake then is ground using standardgrinding methods to produce a powder with a particle size specific toits intended application (step 116 in FIG. 3). For example, if theintended application is to use the powder at low usage levels to fortifya processed food with Vitamin D, a small particle may be desired. If theintended application of the powder is for use as a condiment orseasoning, a larger particle might be preferred.

The mushroom powder particles preferably will pass through a 10 meshscreen (about 2 mm), more preferably pass through a 20 mesh screen(about 850 microns) and more preferably will pass through a 30 meshscreen (about 600 microns) and most preferably will pass through a 70mesh screen (about 210 microns.) A 100 mesh product (about 150 microns)is preferred for food processing applications.

Early trials using cheesecloth as the filter media did not produce asignificant difference in Vitamin D levels when comparing the solubleand insoluble fractions. Subsequent testing using Whatman laboratorygrade filter paper did produce a significant difference in the solubleand insoluble fractions. Ultimately, many different types of filtrationmethods can be used. The filter method used preferably can filter outparticles down to about 1 micron in the insoluble fraction. Anyparticles smaller than 1 micron pass through the filter and arediscarded with the soluble fraction. Besides significantly increasingthe Vitamin D content in the insoluble fraction, filtration of theslurry also helps to achieve additional advantages. By removing themajority of the water from the insoluble fraction, drying times aresignificantly reduced allowing for a large savings in energy. Filtrationalso removes a large portion of the soluble sugars, such as mono anddisaccharides in addition to polysaccharides, a large portion of whichare in the form of mannitol. These materials are very hygroscopic. Byremoving them from the finished dried powder, a free flowing powder isobtained that is less susceptible to high moisture conditions, thusmaking a more stable powder product with an increased shelf life.

Many different mushroom species can be processed in a slurry to convertergesterol to Vitamin D. Our results suggest that all mushroom specieswe have evaluated can be used, specifically including, but not limitedto, white button, agaricus bisporus, shiitake, oyster, maitake, andmixtures thereof.

Referring next to FIG. 1, an apparatus 10 for increasing Vitamin Dcontent in mushroom slurry is shown schematically. Mushrooms andmushroom pieces are shredded, comminuted or pulverized in a mixer 40. Aliquid or fluid, such as water, is mixed with the shredded mushrooms toform a mushroom slurry. The mushroom slurry is introduced to ahomogenizer or pressure reactor 42 to further pulverize or separate themushroom pieces into smaller particles or components within the mushroomslurry. The homogenized mushroom slurry is introduced into a hopper 12that is mounted on a base 16. The hopper 12 terminates in a funnel orexit portion that pours the mushroom slurry 20 onto a vibratory conveyoror oscillating chute 18. The conveyor conveys the mushroom slurry 20into a light chamber 30 that houses an electric glow discharge lamp,such as a xenon pulsed lamp (not shown in FIG. 1).

To control temperature within the light chamber 30, air may be blowninto the light chamber 30 using a blower 34. Connected to the blower 34is an intake hose 36 used to force air into the light chamber 36. Theforced air is then removed from the light chamber 30 using an outlethose 38. We found that it is beneficial, and in some embodiments,necessary, to use the blower 34 because the lamp can generate so muchheat that, without the forced air ventilation and cooling, components ofthe lamp and illumination assembly can melt or otherwise becomeinoperative. The forced air ventilation also helps control thetemperature of the mushroom slurry so that it does not burn or cook.

The conveyor conveys the mushroom slurry through the light chamber 30while the lamp directs UV light radiation onto the mushroom slurry. Theconveyor oscillates or vibrates or shakes to distribute the mushroomslurry on the conveyor, and to direct the radiation onto a significantportion of the surface area of the slurry. In this embodiment, theconveyor vibrates at a rate between 1 Hz and 50 Hz, and is adjusted sothat the slurry passes through the illumination chamber in 6 seconds.Since the lamp pulses 3 times per second, the slurry receives 18 pulseswhile traversing through the illumination chamber. If it is desired toexpose the mushroom slurry to more than 18 pulses, the slurry can becollected and recirculated or passed two or more times through theillumination chamber. Alternatively, two or more illumination chamberscan be used so the slurry passes, in series, through the two or moreillumination chambers.

The irradiated mushroom slurry 20 is then deposited into a container 22as desired.

A more intense UV light-emitting source was found to increase processingspeed. Intense bursts of light can be emitted from pulsed lamps madewith xenon gas. These pulses of light from xenon lamps occur in lessthan 2 milliseconds and create a broad spectrum of UV light. One type ofxenon pulse lamp that has been used is Model RC-747-16 manufactured byXenon Corporation. This xenon pulse lamp, delivers at least 505 joulestotal light energy per pulse. FIG. 3 illustrates the spectrum for theModel RC-747-16 xenon pulse lamp. This type of high intensity lamp emitspulses of UV radiation with an intensity of at least 1.26 J/cm² at 1″from the window face of the lamp.

Preferably, the UV radiation emitted by the UV light-emitting source haswavelengths in the range of about 200 to about 800 nanometers. Withoutintending to be limiting as to mechanism, we believe that it is UV-Bradiation which is most effective in the photoisomerization ofergesterol to Vitamin D2.

Referring next to FIG. 2, an alternative apparatus 10A for increasingVitamin D content in mushroom slurry is shown schematically. In FIG. 2,like structures have the same reference numerals as the apparatus 10 inFIG. 1 and operate in like fashion. Different from the apparatus 10 inFIG. 1, in FIG. 2, the apparatus 10A omits the pressure reactor.Instead, a mixer 50 forms a slurry by mixing a liquid or fluid andmushrooms. A suitable high shear mixer is a Silverson high shear mixerwith changeable mix-heads 52, including a general purpose disintegratingattachment, or a square hole high shear attachment or an emulser headand screen. The different mix-heads may be attached at various stages ofmixing to form a flowable slurry or emulsion.

Another variation as shown in FIG. 2, the container 22 includes apropeller mixer 62 to keep mixing the slurry after it exits the lightchamber 30. The treated slurry may be pumped using a positivedisplacement pump 64, such as a peristaltic pump, for recirculating thetreated slurry to the light chamber for another pass under the UV-lightsource.

The FDA has ruled on the safety of food exposed to xenon lamp pulsedlight exposure.

-   -   Food and Drug Administration Issues Approval for Pulsed UV Light        in the Production, Processing and Handling of Food    -   Code 21CFR179.41, issued by the Food and Drug Administration        (FDA), Department of Health and Human Services, approves the use        of Pulsed UV light in the production, processing and handling of        food.    -   Title 21—FOOD AND DRUGS (Page 438) Chapter I—FOOD AND DRUG        ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES Part        179—IRRADIATION IN THE PRODUCTION, PROCESSING AND HANDLING OF        FOOD Subpart B—Radiation and Radiation Sources Sec. 179.41        Pulsed light for the treatment of food Pulsed light may be        safely used for the treatment of foods under the following        conditions:    -   (a) The radiation sources consist of xenon flashlamps designed        to emit broadband radiation consisting of wavelengths covering        the range of 200 to 1,000 nanometers (nm), and operated so that        the pulse duration is no longer than 2 milliseconds (ms);    -   (b) The treatment is used for surface microorganism control;    -   (c) Foods treated with pulsed light shall receive the minimum        treatment reasonably required to accomplish the intended        technical effect; and    -   (d) The total cumulative treatment shall not exceed 12.0        joules/square centimeter (J/cm\2\.)

The FDA guideline uses pulsed light for surface microorganism control.Mushrooms that are exposed to xenon lamp radiation for 2 millisecondsare within the FDA guideline for food safety. Surprisingly, this shortduration exposure can be sufficient to achieve significant enhancementof Vitamin D in mushrooms.

As the mushroom slurry traverses the UV light exposure area so as toexpose most or all of the individual particles to UV light,significantly higher levels of Vitamin D are achieved. After furtherprocessing through filtration, drying and grinding the resulting powderhas a very high level of Vitamin D. The powder can now economically beused as an all natural, vegetarian source of Vitamin D2 in processedfood products at very low usage levels without dramatically affectingthe flavor, appearance, or cost of the finished product. The powder alsomay have use in animal feed. The powder also may be incorporated intopreparations for topical application to the skin, scalp or hair.

In summary, the apparatus and methods disclosed herein permit continuousand economic production of mushroom powder with extremely high levels ofvitamin D2 on a commercial scale.

EXAMPLES Example 1

Whole mushrooms of the species agaricus bisporus are combined with anequal weight of water and mixed or homogenized into a puree using aWaring blender. The resulting mushroom slurry has suspended mushroomparticles with an average particle size of 150-200 microns. The mushroomslurry then is circulated under a pulsed UV light model RC-747-16manufactured by Xenon Corporation. The mushroom slurry is dried andground into a powder. The resulting mushroom powder has a mass fractionof Vitamin D2 contains at least 10,000 IU/gram of powder.

Example 2

Mushroom slurry is produced as in Example 1 and then passed through apressure reactor model DR-HP-3 with a 0.03″ orifice operating at 3000psi manufactured by IKA Corporation. The pressure reactor destroys orruptures the individual cell walls of the mushroom tissue allowing formore ergosterol to react with the pulsed UV light. The pressure reactorproduces a slurry with suspended mushroom particles having an averageparticle size of 50-100 microns. The mushroom slurry then is circulatedunder the pulsed UV light as in Example 1. The mushroom slurry is driedand ground into a powder. The resulting mushroom powder has a massfraction of Vitamin D2 of at least 20,000 IU/gram of powder.

Example 3

Mushroom slurry is produced as in Example 2. After circulating themushroom slurry under the pulsed UV light, it is filtered to separatethe soluble and insoluble fractions. The soluble fraction containsmostly dissolved polysaccharides does not contain significant level ofVitamin D2 and is discarded. The insoluble fraction, or filter cake, isretained, dried and ground into a powder. The resulting mushroom powderhas a mass fraction of Vitamin D2 of at least 40,000 IU/gram of powder.

Example 4

Mushroom stumps and root material are combined with an equal weight ofwater and mixed or homogenized into a slurry using a Waring blender. Themushroom slurry is passed through a pressure reactor model DR-HP-3manufactured by IKA Corporation. The pressure reactor has a 3-stagechamber with the following combination: 0.03″ orifice with a ½ window,followed by a 0.05″ orifice with no window, followed by a 0.055″ orificewith full windows. The 3-stage chamber allows for greater cell walldestruction. The slurry then is circulated under the pulsed UV light,filtered and dried. The resulting powder produced from the stumps androot material has a mass fraction of Vitamin D2 of at least 15,000IU/gram of powder.

Example 5

Whole mushrooms are combined with an equal weight of water and mixed orhomogenized into a slurry using a Silverson DX60 mixer. A standardgeneral purpose disintegrating head is used at first. Then, a squarehole high shear mix head is used. Finally, an emulser head and screen isused with the mixer. The resulting mushroom slurry comprises particleswith particle sizes of from 50 to 100 μm. The slurry then is circulatedunder the pulsed UV light, filtered and dried. The resulting mushroompowder has a mass fraction of Vitamin D2 of at least 40,000 IU/gram ofpowder.

TABLE 1 Sample Description: Vitamin D IU/gram Example 1 11,826 Example 219,758 Example 3 (unseparated) 14,674 Example 3 (solid portion) 53,661Example 3 (liquid portion) 79 Example 4 16,456 Example 5 40,000

Example 6

Whole mushroom pieces of the species agaricus bisporus are combined withan equal weight of water and mixed or homogenized into a slurry or pureeusing a Silverson model DX60 high shear mixer. The resulting slurry hassuspended mushroom particles with an average particle size of 50 to 500microns. The mushroom slurry is then continuously circulated on aconveyor under a medium pressure mercury vapor UV light source fromHeraeus (Model M110-UV) for 5 hours, making more than 5 passes. Themushroom slurry is filtered and the filter cake is dried and ground intoa powder. The resulting mushroom powder has a mass fraction of Vitamin Dof at least 40,000 IU/gram of powder.

Example 7

Whole mushroom pieces of the species agaricus bisporus are combined withan equal weight of water and mixed or homogenized into a slurry or pureeusing a Silverson model DX60 high shear mixer. The resulting slurry hassuspended mushroom particles with an average particle size of 50 to 500microns. The mushroom slurry is then continuously circulated on aconveyor under a microwave powered Fusion UV lamp from Heraeus (ModelF300S) for 5 hours, making more than 5 passes. The mushroom slurry isfiltered and the filter cake is dried and ground into a powder. Theresulting mushroom powder has a mass fraction of Vitamin D of at least20,000 IU/gram of powder.

Example 8

Whole mushroom pieces of the species agaricus bisporus are combined withwater in a ratio of 1:4, mushrooms:water, and mixed or homogenized intoa slurry or puree using a Silverson model DX60 high shear mixer. Theresulting slurry has suspended mushroom particles with an averageparticle size of 50 to 500 microns. The mushroom slurry is then passedone time only on a conveyor for 30 seconds under a medium pressuremercury vapor light UV from Heraeus (Model M110-UV). The mushroom slurryis filtered and the filter cake is dried and ground into a powder. Theresulting mushroom powder has a mass fraction of Vitamin D of at least65,000 IU/gram of powder.

The invention has been illustrated by detailed description and examplesof particular embodiments. Various changes in form and detail may bemade to the illustrative embodiments without departing from the spiritand scope of the present invention. Therefore, the invention must bemeasured by the claims and not by the description of the examples or theparticular embodiments.

1. An apparatus for increasing vitamin D content of mushrooms,comprising: a lamp configured to emit ultraviolet light, said lampcapable of emitting light with wavelengths in the range of about 200 toabout 800 nanometers; a homogenizer configured to pulverize or comminutemushrooms into particles having an average particle size in the range ofabout 200 microns or smaller to form a mushroom slurry of mushroomparticles having an average particle sizes of about 200 microns orsmaller suspended in liquid; a vibrating conveyor configured to conveyand vibrate the mushroom slurry of mushroom particles suspended inliquid for exposure to light emitted by the lamp; a filter or othermeans to separate the irradiated mushroom slurry into a soluble fractionand an insoluble fraction; and a grinder configured to grind theinsoluble fraction into a powder having powder particle size that passesthrough a 70 mesh screen.
 2. The apparatus of claim 1, furthercomprising: a light chamber housing the lamp; and means for controllingtemperature within the light chamber.
 3. The apparatus of claim 1,wherein the vibrating conveyor is selected from the group consisting of:vibrating conveyor belt, shaker table, vibrating pan and vibratingchute.
 4. The apparatus of claim 1, further comprising: a recycle lineto redirect mushroom slurry onto the conveyor for another exposure toultraviolet light emitted from the lamp.
 5. The apparatus of claim 1,wherein the filter or other means to separate the irradiated slurry intoa soluble fraction and an insoluble fraction is selected from the groupconsisting of: filter paper, filter bag, filter press, and centrifuge.6. The apparatus of claim 1, wherein the lamp is selected from the groupconsisting of: electric glow discharge lamps, medium pressure mercuryvapor lamps, low pressure mercury vapor lamps, microwave powered fusionultraviolet lamps, light emitting diodes (LEDs), and low pressureamalgam lamps.
 7. The apparatus of claim 1, wherein the lamp emitspulses of light with wavelengths in the range of about 200 to about 800nanometers.
 8. A method for increasing vitamin D content of mushrooms,comprising: pulverizing fresh mushrooms and/or fresh mushroom pieces tocreate a mushroom slurry of mushroom particles having a size in therange of about 500 microns or smaller that are suspended in a liquid,wherein the ratio of liquid to mushroom particles in the slurry is atleast 3:1 (by weight); and irradiating the mushroom slurry withultraviolet light with wavelengths in the range of about 200 to about800 nanometers.
 9. The method of claim 8, wherein irradiating is with asource of ultraviolet light and the source of ultraviolet light isselected from the group consisting of: electric glow discharge lamps,medium pressure mercury vapor lamps, low pressure mercury vapor lamps,microwave powered fusion ultraviolet lamps, light emitting diodes(LEDs), and low pressure amalgam lamps.
 10. The method of claim 8,further comprising: conveying the mushroom slurry past the source ofultraviolet light with a conveyor selected from the group consisting of:vibrating conveyor, shaker table, vibrating pan and vibrating chute. 11.The method of claim 10, further comprising: re-conveying the mushroomslurry past the source of ultraviolet light.
 12. The method of claim 8,further comprising: separating the mushroom slurry into soluble andinsoluble fractions.
 13. The method of claim 12, further comprising:drying the insoluble fraction; and grinding the insoluble fraction toform a mushroom powder.
 14. The method of claim 13, wherein saidmushroom powder has a mass fraction of Vitamin D2 of at least 40,000IU/gram of mushroom powder.
 15. The method of claim 13 wherein themushroom powder has a moisture content of less than about 30% moistureby weight.
 16. The method of claim 8, wherein the mushroom particles aremade from one or more fresh mushrooms selected from the group consistingof: white button mushrooms, brown portobello mushrooms, shiitakemushrooms, oyster mushrooms, agaricus bisporus, and mixtures thereof.17. A consumable food product comprising mushroom powder made by themethod of claim 13, said powder having a vitamin D2 content of at least40,000 IU/gram of powder.
 18. A consumable food product comprisingmushroom powder made by the method of claim 13, said powder having avitamin D2 content of at least 20,000 IU/gram of powder and an averageparticle size in the range of about 210 microns and smaller.
 19. Aconsumable food product comprising mushroom powder having a vitamin D2content of at least 40,000 IU/gram.
 20. The consumable food product ofclaim 19, wherein said mushroom powder has an average particle size inthe range of about 210 microns and smaller.